Transmit Operation; Receive Operation - IBM Series 1 User Manual

The interrupt condition codes are subject to the following
rules and considerations:
1)
The attention and exception codes are associated only
with receive operations; the device end code with a
transmit operation.
2) The attention and exception codes are associated with
operations initiat~d
by
the device. The device end
code is associated with operations initiated by the
program.
3) Attention and exception interrupts may be posted
asynchronously to the device end interrupt. Since
interrupt code presentation does not accommodate both
exception and device end codes during interrupt
presentation, the exception code takes precedence OYer
the device end code at interrupt presentation time if
both interrupts have been posted. The presentation and
acceptance of the exception code does not reset a
pending device end interrupt.
The meaning of the interrupt condition codes is as follows:
CC2 Indicates that the adapter has coapleted at least one
overrun receive operation.
A
device end interrupt may
be pending, but the exception code has taken precedence
in presentation.
ee3
Indicates completion of a transmit operation as a
result of a write command or indicates completion of an
IPL operation. No exception interrupt has been posted
at accept time.
CC4 Indicates completion of a normal receive operation.
Note that data can be read while the adapter is
executing an overrun receive operation up to the time
the exception interrupt is posted.
CC6 Indicates that the adapter has completed a normal
receive operation and has completed at least one
overrun receive operation. A device end may be
pending, but the exception code has taken precedence in
presentation.
CC7 Indicates that the conditions that cause CC4 and
ee3
have occurred.
Refer to the prerequisite publications listed in the
"Preface" of this manual for a detailed explanation of the
differences between condition codes 2, 4, and 6.
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